ORAL · 2016. 8. 31. · Oral Implantology The European Journal of Oral Implantology is published...

EJOI

ORAL IMPLANTOLOGYEUROPEAN JOURNAL OF

Official publication of the British Society of Oral Implantology (BSOI),the Italian Society of Oral Surgery and Implantology (SICOI),

the Danish Society for Oral Implantology (DSOI),the German Association of Oral Implantology (DGI),

the Spanish Society of Implantology (SEI),and the British Academy of Implant & Restorative Dentistry (BAIRD)

VOLUME 7 / SUPPLEMENT 2SUMMER 2014

Patient centered management and optimal number of implants in the treatment of edentulismA consensus conferenceUniversity of Mainz, Germany27th and 28th March 2014

S86 n EDITORIAL

Eur J Oral Implantol 2014;7(Suppl2):S86

Editorial

This supplemental issue of EJOI is dedicated to the Foundation for Oral Rehabilitation (FOR) consen-sus conference, ‘Patient centered management and optimal number of implants in the treatment of edentulism’, which was held on the 27th and 28th March, 2014. Scientific associations and other organisations using EJOI as their official publica-tion are welcome to publish the outcome of their consensus conferences or working groups in the journal.

It is the policy of EJOI that these publications will not be peer reviewed as they are normally. Conse-quently, readers are encouraged to critically evaluate the findings presented, as they would with all scien-tific publications. Guidance on how to develop criti-cal skills for research, analysis and the evaluation of scientific publications (an important mission of EJOI) can be found in the ‘educational articles’1-4 and on the EQUATOR (Enhancing the QUAlity and Trans-parency Of health Research) website (http://www.equatornetwork.org/). The EQUATOR Network is aimed at helping authors properly report their health research studies. After selecting the ‘Resource Cen-tre’, please click on the ‘Library for health research

reporting’ and you will access a comprehensive list of reporting guidelines, organised by study type. More specifically, to evaluate systematic reviews please go to the PRISMA transparency guidelines (http://www.prisma-statement.org/).

The results of consensus conferences or work-ing groups can be interpreted differently, depending on people’s perspectives and circumstances. Please consider the conclusions presented carefully. They are the opinions of the review authors, and are not necessarily shared by EJOI editors.

We would like to thank all contributors to the present supplement for their efforts.

Marco Esposito and Michele Nieri

1. Worthington HV, Esposito M, Nieri M, Glenny AM. What is a systematic review? Eur J Oral Implantol 2008;1:235–238.

2. Glenny AM, Nieri M, Worthington H, Espostio M. The importance of the study design: from the case report to the randomised controlled clinical trial. Eur J Oral Implantol 2008;1:317–321.

3. Nieri M, Glenny AM, Worthington H, Esposito M. How to interpret meta-analyses of randomised clinical trials. Eur J Oral Implantol 2009;2:61–66.

4. Glenny AM, Worthington HV, Esposito M, Nieri M. What are clinical guidelines? Eur J Oral Implantol 2009;2:145–148.

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Eur J Oral Implantol 2014;7(Suppl2):S87–S88

GUEST EDITORIAL

Guest editorial

Oral rehabilitation of complete edentulism by means of implants is, and has been for decades, a predict-able treatment option. It provides an improved qual-ity of life, clearly superior to what can be achieved by mucosally retained dentures. But when the question is raised of how many implants one needs to properly deal with the rehabilitation of edentulous patients, opinions are sometimes country-specific, while sci-ence should be borderless.

The Foundation for Oral Rehabilitation (F O R) took up the challenge. Being a global network of experts and clinicians it always refers to scientifically sound and well-proven data, which are universally accepted. A number of reputed researchers and cli-nicians were selected to tackle the question of the number of implants needed, in a thoroughly scien-tific manner. Their selection was based on exper-tise, number of publications and their citation index related to this theme. Each one received a specific subject to critically review in the literature, and if data were sufficiently available to provide a meta-analysis. After exchanging their manuscripts, the experts met during 2 days at the University of Mainz. Travel and hotel expenses were taken care of by F O R, but no other compensation was provided.

For any elective surgery, the patient should be involved in opting among the wide range of treat-ment alternatives. All participants chose the patient-centred viewpoint as a starting point. For a remov-able overdenture, one can choose whether to have it on 2 or 4 implants in the mandible and 4 or more implants in the maxilla. Fixed prostheses are gener-ally placed on 5 or 6 implants and sometimes even more in the maxilla.

When only a limited jawbone volume remains, it can be necessary to consider bone augmentation procedures to (optimally) place a sufficient number

of implants to support a fixed dental prosthesis with a long-term predictable outcome. The key question is whether a more limited number of implants, than the classical 5 to 6 and more, suffice. A more limited number of implants could avoid the invasiveness of bone augmentation/grafting procedures. A review of the literature (Nkenke and Neukam) underlined that, as an intraoral donor site for autologous bone grafting, the mandibular ascending ramus is pref-erable. The symphyseal area leads to the highest (incidence of) morbidities. The posterior iliac crest is a good alternative but implies mostly general an-aesthesia.

Another meta-analysis (Al-Nawas and Schieg-nitz) proved that the survival rate of oral implants placed in conjunction with augmentation procedures is as good with bone substitute material as with au-tologous bone grafts. Nevertheless, the bone aug-mentation procedure by itself is more invasive and more prone to postoperative pain and discomfort than the straightforward (flapless) placement of implants. Thus, if the treatment is patient-centred, avoiding bone augmentation should be considered. Patient satisfaction with graftless solutions is indeed very high and patients’ preference to minimally inva-sive implant surgery well established (Pommer and Watzek).

The key question then becomes what should be the minimal/optimal number of implants to insure a reliable long-term outcome for the (fixed) prosthetic rehabilitation. Two decades ago (Brånemark et al1), it was shown in a large-scale retrospective study that the 10-year survival in edentulous patients of fixed dental prostheses on either 4 or on 6 implants was not significantly different. The tradition to insert at least 5 to 6 implants in edentulous jaws thus became questionable. Since very high survival rates are pres-

Wilfried Wagner, Prof Dr DrUniversity Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany

Daniel van Steenberghe, MD, PhD, Drhc, HFRCS (Irl) em. Professor, Faculty of Medicine, Catholic University Leuven, Belgium

GUEST EDITORIALS88 n


ently reached by implants with moderately rough surfaces, the concept of inserting supplementary implants just to avoid a revision surgery should one implant fail became more or less obsolete.

Furthermore, biomechanical calculations prove that with 4 implants to support a complete cross-arch fixed reconstruction, strains in the bone or at the bone-implant interface remain within the safe range (Brunski). Tilted implants, to insure a proper anterior-posterior spread, can even be subject to lower forces than axial ones (Del Fabbro and Cere-soli). Furthermore, the marginal bone level around tilted implants does not significantly differ from that around axial implants. The latter offers the possibil-ity to achieve a good anterior-posterior spread with few implants.

Functional aspects of implant-supported reha-bilitations have been investigated by different meth-odologies. The number of implants supporting the prostheses does not appear as a relevant factor in the functional qualities (Dellavia et al).

When segmentation of the fixed cross-arch framework is necessary, more than 4 implants are needed (Mericske-Stern and Worni), which raises the treatment cost and can render a bone augmenta-tion procedure indispensable. One may wonder why CAD-CAM technologies, which do reach the neces-sary precision of fit, are not used in these instances to keep the treatment less invasive.

We both feel privileged to coordinate this first F O R consensus conference. The multidisciplinary interactions favoured cross-fertilisation but never-theless led to an iteratively written consensus docu-ment, which was unanimously approved.

The conclusions of this workshop should lead cli-nicians to also consider, for the benefit of their eden-tulous patients, less invasive procedures. Established scientific data, which should always prevail on tradi-tions, do indeed prove that for complete edentulism, unless specific aesthetic and/or functional demands are pressing, 4 implants only can already provide a predictable anchorage for fixed prostheses.

Wilfried Wagner [email protected]

Moderators of the Consensus meeting

1. Brånemark PI, Svensson B, van Steenberghe D. Ten-year survival rates of fixed prostheses on four or six implants ad modum Brånemark in full edentulism. Clin Oral Implants Ress1995;6:227–231.

Daniel van Steenberghe [email protected]

The group of experts from left to right: Drs Gerry Raghoebar, Bernhard Pommer, Claudia Dellavia, John Brunski, Wilfried Wagner, Daniel van Steenberghe, Emeka Nkenke, Massimo Del Fabbro, Bilal Al-Nawas, Regina Mericske-Stern, Georg Watzek.

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CONTENTS

European Journal of Oral ImplantologySupplement 2, Summer 2014

Contents

EDITORIAL S86Marco Esposito

GuEST EDITORIAL S87Wilfried Wagner, Daniel van Steenberghe

REvIEW ARTICLE Patients’ preferences towards minimally invasive treatment alternatives for implant rehabilitation of edentulous jaws S91Bernhard Pommer, Georg Mailath-Pokorny, Robert Haas, Dieter Busenlechner, Rudolf Fürhauser, Georg Watzek

CLINICAL ARTICLEBiomechanical aspects of the optimal number of implants to carry a cross-arch full restoration S111John B. Brunski

REvIEW ARTICLESOptimal number of oral implants for fixed reconstructions: A review of the literature S133Regina Mericske-Stern, Andreas Worni

Functional jaw muscle assessment in patients with a full fixed prosthesis on a limited number of implants: A review of the literature S155Claudia Dellavia, Riccardo Rosati, Massimo Del Fabbro, Gaia Pellegrini

CLINICAL ARTICLEThe fate of marginal bone around axial vs. tilted implants: A systematic review S171Massimo Del Fabbro, Valentina Ceresoli

REvIEW ARTICLE A systematic review of implant-supported overdentures in the edentulous maxilla, compared to the mandible: How many implants? S191Gerry M. Raghoebar, Henny J.A. Meijer, Wim Slot, James J.R. Huddleston Slater, Arjan Vissink

CLINICAL ARTICLEAutogenous bone harvesting and grafting in advanced jaw resorption: Morbidity, resorption and implant survival S203Emeka Nkenke, Friedrich W. Neukam

REvIEW ARTICLE Augmentation procedures using bone substitute materials or autogenous bone – a systematic review and meta-analysis S219Bilal Al-Nawas, Eik Schiegnitz

CONSENSuS STATEMENTSPatient-centred rehabilitation of edentulism with an optimal number of implants S235

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European Journal of Oral Implantology

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Editors

Marco Esposito, Arcore, Italy (Editor-in-Chief)Jerome Lindeboom, Amsterdam, The NetherlandsMichele Nieri, Florence, ItalySøren Schou, Aarhus, Denmark

Official publication of the British Society of Oral Implantology (BSOI), the Italian Society of Oral Surgery and Implantology (SICOI), the Danish Society for Oral Implantology (DSOI),the German Association of Oral Implantology(DGI),the Spanish Society of Implantology (SEI), and the British Academy of Implant & Restorative Dentistry (BAIRD)

Editorial Board

Carlos Aparicio, SpainKarl Bishop, UKIan Brook, UKJason Buglass, UKGioacchino Cannizzaro, ItalyMatteo Chiapasco, ItalyNoel Claffey, IrelandStJohn Crean, UKRubén Davó, SpainNikolaos Donos, UK Pietro Felice, ItalyAnne-Marie Glenny, UKRonnie Goené, The NetherlandsKlaus Gotfredsen, DenmarkStefano Gracis, ItalyTommaso Grandi, Italy Kerstin Grondahl, SwedenUeli Grunder, SwitzerlandM Gabriella Grusovin, Italy Dominic Hassall, UKFederico Hernández-Alfaro, SpainSøren Hillerup, DenmarkFlemming Isidor, DenmarkReinhilde Jacobs, Belgium

Torsten Jemt, SwedenSøren Jepsen, GermanyRonald Jung, SwitzerlandMatthias Kern, GermanyFouad Khoury, GermanyYe Lin, ChinaHassan Maghaireh, UK Chantal Malevez, BelgiumPaulo Maló, PortugalMauro Merli, ItalyKen Nicholson, UKAlan Payne, New ZealandRoberto Pistilli, Italy Bjarni E Pjetursson, IcelandStefan Renvert, SwedenMariano Sanz, SpainPaul Stone, UKHendrik Terheyden, GermanyTiziano Testori, ItalyGeorg Watzek, AustriaDieter Weingart, GermanyHelen V Worthington, UKOtto Zuhr, Germany

n S91


REVIEW ARTICLE

Bernhard Pommer, DDS, PhD Associate Professor, Oral Surgeon and Researcher, Academy for Oral Implan-tology, Vienna, Austria

Georg Mailath-Pokorny, DDS, MD, PhDUniversity Professor, Oral Surgeon and Founding Partner, Academy for Oral Implantology, Vienna, Austria

Robert Haas, DDS, MD, PhDUniversity Professor, Oral Surgeon and Founding Partner, Academy for Oral Implantology, Vienna, Austria

Dieter Busenlechner, DDS, PhDAssociate Professor, Oral Surgeon and Partner, Academy for Oral Implan-tology, Vienna, Austria

Rudolf Fürhauser, DMD, MD, PhDChief Physician, Prosthodon-tist and Founding Partner, Academy for Oral Implantol-ogy, Vienna, Austria

Georg Watzek, DDS, MD, PhDUniversity Professor, Oral Surgeon and Founding Partner, Academy for Oral Implantology, Vienna, Austria

Correspondence to:Priv. Doz. Ass. Prof. Dr. Bernhard PommerAcademy for Oral Implan-tology GmBH & Co KGLazarettgasse 19/DG, A-1090 Vienna, AustriaTel: +43 1 4028668Fax: +43 1 4028668 10Email: pommer@ implantat akademie.at

Bernhard Pommer, Georg Mailath-Pokorny, Robert Haas, Dieter Busenlechner, Rudolf Fürhauser, Georg Watzek

Patients’ preferences towards minimally invasive treatment alternatives for implant rehabilitation of edentulous jaws

Key words dental implants, implant-supported dental prosthesis, quality of life, patient prefer-ence, patient satisfaction

Purpose: To evaluate patient satisfaction, oral health-related quality of life, and patients’ preferences towards minimally invasive treatment options for graftless rehabilitation of complete edentulism by means of dental implants.Material and methods: A MEDLINE search of literature in the English language up to the year 2013 was performed to summarise current evidence from the patient’s perspective. The final selection included 37 studies reporting on minimally invasive implant treatment of 648 edentulous maxillae and 791 edentulous mandibles in 1328 patients, via a total of 5766 implants.Results: Patient satisfaction averaged 91% with flapless implant placement (range: 77 to 100%), 89% with short implants, 87% with narrow-diameter implants (range: 80 to 93%), 90% with a reduced number of implants (range: 77 to 100%), 94% with tilted implant placement (range: 58 to 100%), and 83% with zygomatic fixtures (range: 50 to 97%). Indirect comparison yielded patient preference towards tilted implant placement compared to a reduced number of implants (P = 0.036), as well as to zygomatic implants (P = 0.001).Conclusions: While little evidence on patients’ preferences towards minimally invasive treatment alternatives vs. bone augmentation surgery could be identified from within-study comparison, it may be concluded that patient satisfaction with graftless solutions for implant rehabilitation of completely edentulous jaws is generally high. Comparative effectiveness research is needed to substantiate their positive appeal to potential implant patients and possible reduction of the indication span for invasive bone graft surgery.

Conflict-of-interest notification: The authors declare that they have no conflict of interest.

n Introduction

During the past decade, there has been an obvi-ous trend in oral health care towards techniques attempting to provide optimum service for patients with the minimal amount of treatment1. Interest for minimally invasive procedures as standard treatment is notably growing in the field of oral implantology2.

While modification of the patient’s jaw anatomy by bone augmentation surgery to allow placement of longer and wider implants has been generally con-sidered the best treatment strategy in the past, adap-tation of implant dimensions and positions to the existing anatomy may represent a more appropriate solution in cases of severe atrophy of the residual alveolar bone3. The option of a minimally invasive

Pommer et al Patient preferences towards minimal invasionS92 n


technique – per definition – appeals to a greater number of potential implant patients and is fre-quently associated with economic benefits4. Implant surgery may be termed ‘minimally invasive’ referring to avoidance of bone grafts5, and/or prevention of intra- and postoperative patient morbidity in terms of pain6, swelling7, bleeding8, or expended operat-ing time9. Transmucosal healing modality10 or imme-diate implant placement11, by contrast, may reduce the number of surgical interventions, however, cir-cumvent only insignificant trauma and do not strictly reflect the concept of minimal invasion. The same is true for prosthetic concepts, such as immediate provisionalisation or early loading12 in spite of their inherent advantages of reduced treatment duration relevant to patients. Reduction of surgical invasion may thus be achieved by either:• reduction in the extent of mucosal flap elevation:

flapless implant placement frequently combined with CAD/CAM surgical templates13 or intraop-erative navigation14

• reduction of the size of implants used: short implants less than 10 mm in length15, or narrow-diameter implants less than 3.75 mm in width16

• reduction of the number of implants placed17, or• maximum use of anatomical buttresses: tilted18

or zygomatic implants19.

Patient satisfaction represents one of the most fun-damental goals to achieve in oral rehabilitation20. Treatment evaluation in evidence-based medicine and dentistry should thus embrace the opinion and attitude of patients as a variable of therapeutic suc-cess21. Outcomes of oral implant therapy have tra-ditionally been described in terms of survival rates, clinical and radiological surrogate parameters and durability of implant superstructures22, however, patient-based outcome measures are considered essential to complement the clinical component for more comprehensive assessment of health status and the impact on the recipient (Table 1)23-25. Com-plete edentulism can substantially affect oral and general health, as well as overall quality of life26. Patients may suffer pain in the denture-bearing area, impaired chewing efficiency and nutrition due to limited retention and stability of conventional prostheses27. As Professor Per-Ingvar Brånemark famously put it28: “The edentulous patient is an

Table 1 Outcome measures to evaluate oral implant treatment.

Implant-related outcome measures

implant survival rate percentage of implants in situ

implant success rate percentage of implants fulfilling certain criteria of success

marginal bone remodelling radiologic peri-implant crestal bone position (marginal bone level) or alterations (marginal bone resorption)

peri-implant mucosal health pocket probing depth, bleeding on probing, sulcus bleeding index, and presence of keratinised mucosa

peri-implant mucosal aesthetics professional rating of “pink” aesthetics, e.g. via the Pink Esthetic Score23

Denture-related outcome measures

denture survival rate percentage of dentures in situ (in spite of potential implant loss in cases of sus-tained usability)

technical complications frequency of mechanical damage of the implant components and suprastructures or maintenance work

objective masticatory function masticatory performance in terms of bite force, food break-down, mastication time or electromyographic jaw muscle activity24

objective phonetic function speech intelligibility, articulation and oromyofunctional behaviour25

Patient-related outcome measures

oral health-related quality of life (OHRQoL)

hierarchy of functional, psychological and social parameters assessed, e.g. via the Oral Health Impact Profile (OHIP)

patient satisfaction subjective visual analogue scale (VAS) ratings regarding stability, chewing efficien-cy, phonetics, aesthetics, or ease of cleaning

patient preference patients‘ choice of preferred treatment

Pommer et al Patient preferences towards minimal invasion n S93


amputee, an oral invalid, to whom we should pay total respect and rehabilitation ambitions.” The aim of the present systematic review was to evaluate patient satisfaction, oral health-related quality of life, and patients’ preferences towards minimally invasive treatment options for graftless rehabilitation of com-plete edentulism.

n Materials and methods

The authors searched for clinical scientific literature in the English language via the US National Institutes of Health free digital archive of biomedical and life sciences journal literature (Pubmed MEDLINE). The last search was performed on 23 December 2013. The search term ‘dental implant’ was combined with ‘patient satisfaction’, ‘patient perspective’, ‘patient preference’, ‘minimally invasive’, ‘flapless’, ‘short’, ‘reduced diameter’, ‘narrow diameter’, ‘tilted’ and ‘zygomatic’. After exclusion of 65 duplicates, a total of 424 abstracts were screened. Studies were con-sidered if they met the following eligibility criteria: 1) clinical investigations; 2) reporting on patient-based outcome measures (patient satisfaction, oral health-related quality of life, or patient preference); 3) of minimally invasive 4) graftless implant treatment 5) in completely edentulous patients.

A total of 81 papers were screened in full text, of which 33 did not fulfil eligibility criterion 2, 14 did not fulfil eligibility criterion 3, and 18 did not fulfil eligibility criterion 5 (listed in the APPENDIX; avail-able online). After exclusion of 1 duplicate publica-tion reporting on a patient cohort already included, 15 studies were selected as preliminary candidates. Moreover, the references of all eligible original pub-lications as well as those of relevant review articles and meta-analyses29-72 were screened, resulting in an additional 22 included studies. Study selection was performed in duplicate (BP and GW) and disa-greements were resolved by consensus.

Descriptive analysis of study characteristics included: study design; number of patients and jaws treated; number of implants placed per jaw and in total; length of follow-up; scale used for outcome assessment; and performance of within-patient comparison (pre-vs. post-implantation). Weighted mean rates of patient satisfaction were calculated

for each treatment strategy after conversion of indi-vidual study results to per cent scale (i.e. a rating of 4 in a 5-point Lickert scale was expressed as 80%). Likewise, Oral Health Impact Profile (OHIP) ratings were divided by the maximum total value (i.e. 196 for the full version OHIP-49 using a 0-4 Lickert scale) to achieve normalisation of OHIP versions and en-able outcome comparison73.

n Results

The final selection included 37 studies reporting on minimally invasive graftless implant treatment of 648 edentulous maxillae and 791 edentulous mandibles in 1328 patients via a total of 5766 implants. Patient-based outcome measures constituted of treatment satisfaction (34 studies), oral health-related quality of life (4 studies) or patient preferences (2 studies). The following minimally invasive treatment options were investigated: flapless implant placement (5 studies, 90 patients, 427 implants); short implants (1 study, 19 patients, 76 implants); narrow-diameter implants (7 studies, 152 patients, 523 implants); reduced number of implants (7 studies, 320 patients, 992 implants); tilted implant placement (11 studies, 660 patients, 3266 implants); and zygomatic fixtures (6 studies, 87 patients, 482 implants).

n Flapless implant placement

Hof and co-workers (2014)74 investigated 22 patients (16 women, 6 men, mean age: 61 years) with 20 edentulous maxillae and 11 eden-tulous mandibles in a cross-sectional questionnaire-based interview survey. Inclusion criteria involved patients seeking implant treatment without history of previous implant surgery. Patient preferences were assessed by polar questions regarding their disposi-tion to receive flapless guided implant placement. A total of 77% were keen to avoid open flap surgery, while the remainder did not favour one treatment strategy over the other (Table 2).

Nkenke and co-workers (2007)75 investigated 10 patients (2 women, 8 men, mean age: 65 years) all with edentulous maxillae in a prospective com-parative study with a follow-up of 1 year. Inclusion criteria involved the placement of 6 implants into



native anterior maxillary bone and matched patients’ demographics (equal gender, maximum age differ-ence: 5 years, maximum weight difference: 10 kg) between the two treatment groups: 5 patients were subjected to flapless implant placement using CAD/CAM surgical templates after virtual treatment planning in a computed tomographic scan (Pro-cera; Nobel Biocare, Zurich, Switzerland), while in the remaining 5 patients mucoperiosteal flaps were elevated. Patient satisfaction was assessed on a visual analogue scale (VAS) regarding the follow-ing questions: 1) Would you have this procedure done again?; 2) Did you recognise bleeding during surgery?; 3) Was the duration of surgery accept-able?; and 4) Would you recommend this procedure to a friend? (0 = maximal agreement to 10 = maxi-mal disagreement). VAS-ratings regarding pain and discomfort differed significantly (P < 0.01) between open (57.2, 61.2, and 23.6) and flapless implant placement (11.6, 9.6, and 4.6), 6 h, 1 day and 7 days after surgery, respectively. Patients subjected to flap elevation were less likely to repeat the procedure, recognise intraoperative bleeding, accept the dura-tion of surgery, and recommend the procedure to a friend.

Papaspyridakos and Lal (2013)76 investigated 14 patients (10 women, 4 men, mean age: 58) with 6 edentulous maxillae and 10 edentulous mandibles in a prospective study with a mean follow-up of 3 years. Inclusion criteria involved mouth opening of at least 50 mm to accommodate for the surgical instrumentation. Flapless placement of 103 implants was performed using virtual planning software (NobelGuide, Nobel Biocare) and stereolithographic

surgical templates. The patients received 14 full arch and 2 segmented porcelain fused to zirconia implant fixed prostheses (Procera, Nobel Biocare). Patient satisfaction was assessed by polar questions regard-ing aesthetic outcome and occlusal function. Great patient satisfaction with function and aesthetics was recorded for all these patients that had undergone flapless surgery.

van Steenberghe and co-workers (2005)77 investi-gated 27 patients (mean age: 63 years) with edentulous maxillae in a prospective multicentre study, of which 24 patients completed the 1-year follow-up. Inclusion criteria involved sufficient bone volume to harbour at least 6 implants of at least 10 mm in length. A total of 184 implants (Brånemark MK III TiU, Nobel Biocare) were placed according to the Teeth-in-an-Hour con-cept using double-scan spiral computed tomography, 3D treatment planning software (NobelGuide, Nobel Biocare) and stereolithographic surgical templates to allow for guided flapless implant placement. Immedi-ate provisional restoration was performed using pre-fabricated customised fibre-reinforced acrylic full-arch fixed prostheses. Patient satisfaction was assessed at 3 months and after 1 year of loading (0 = poor to 10 = excellent outcome) regarding speech, oral function, aesthetics and tactile sensation. While after 3 months half of the patients were not completely satisfied with their speech, at the 1-year follow-up, 88% judged aesthetics as either excellent or good. Function and tactile sense was perceived as excellent or good by all patients after 1 year.

Wittwer and co-workers (2007)78 investigated 20 patients (6 women, 14 men, mean age: 64 years) with edentulous mandibles in a prospective

Table 2 Studies on patient satisfaction with flapless implant placement in edentulous jaws (mx = maxilla, md = mandible): study design (cross = cross-sectional study, pro = prospective study), number of patients (Patient no.), implants placed per patient (Impl/pat), length of follow-up (in years), assessment scale (+/– = polar questions), and within-patient comparison pre- vs. post-implantation.

Study design

Jaw Patient no. Impl/pat

Follow- up Scale Within patient

Hof et al, 201474 cross 20 mx 11 md

22 +/- no

Nkenke et al, 200775 pro mx 5 6 1 a 100-0 no

Papaspyridakos & Lal, 201376 pro 6 mx 10 md

14 5-8 3 a +/- no

van Steenberghe et al, 200577 pro mx 24 6-8 1 a 0-10 no

Wittwer et al, 200778 pro md 20 4 +/- no



pilot study. Inclusion criteria involved residual bone height of more than 15 mm in the anterior mandible and complete edentulism for at least 1 year prior to surgery. Flapless placement of 4 implants (Anky-los, Dentsply Friadent, Mannheim, Germany) in the interforaminal region was performed using the VISIT implant planning and navigation software (Univer-sity of Vienna), allowing for real-time navigation after matching the patient’s computed tomographic scans with a point-to-point registration. All patients received bar-retained overdentures. Patient satisfac-tion was assessed by a dichotomous variable: the procedure was claimed to be well tolerated by all 20 patients (100%).

n Short implants

Stellingsma and co-workers (2003)79 investigated 60 patients (50 women, 10 men, mean age: 59 years) with edentulous mandibles in a prospective compara-tive study with a follow-up of 1 year. Inclusion cri-teria involved long-term edentulism (patients wear-ing their third complete lower denture on average). While the other 2 groups in the study were subjected to bone augmentation (19 patients) or transmandib-ular implants (20 patients), the remaining 19 patients received 4 short implants (IMZ, Friatec) in the anterior mandible. However, implant lengths were 8 or 11 mm, thus not all met the generally accepted definition of short implants of less than 10 mm in length15. Patient satisfaction was assessed on a 10-point rating scale (0 = completely dissatisfied to 10 = completely satis-fied). In addition, denture satisfaction was assessed using a validated questionnaire80 consisting of eight items focusing on the function of upper and lower dentures, and on specific features such as aesthet-ics, retention and functional comfort (5-point rat-ing scale). Patients’ experiences in the surgical phase were more negative than expected for 25% of short

implant patients vs. 50% of augmentation patients. Postoperative pain lasting longer than 1 week also differed significantly (20% vs. 85%). Overall satis-faction with short implant therapy increased signifi-cantly from 4.4 before treatment to 8.9 after implant placement (+45%), but however, did not differ sig-nificantly (increase from 4.3 to 7.9) compared to the augmentation group (Table 3).

n Narrow-diameter implants

Brandt and co-workers (2012)81 investigated 24 patients (age range: 35 to 75 years) with eden-tulous mandibles in a 2-year follow-up study. Inclusion criteria involved presence at the follow-up examinations. A total of 96 narrow-diameter implants (MDL, Intra-Lock) with a diameter of 2.0 mm and an O-ball attachment were placed in the anterior mandible and loaded immediately. Patient satisfaction was assessed on a scale from 1 = extremely poorer than before, 2 = consider-ably poorer than before, 3 = slightly poorer than before, 4 = the same as before, 5 = slightly better than before, 6 = considerably better than before, to 7 = extremely better than before: 1) How well can you bite with your present dentures after occlusal adjustments as compared with before im-plant placement?; 2) Rate your satisfaction from your present dentures after implant placement as compared with before implant placement?; 3) How secure do you feel with your present dentures after implant placement compared with your present dentures before implant placement?; and 4) How much have your present dentures, after implant placement, affected your speech compared with your present denture before occlusal adjustements? Mean patient satisfaction was 3.8 (54%) prior to implant placement was 6.5 (93%) after 2 years of loading (Table 4).

Table 3 Studies on patient satisfaction with short implants in the edentulous mandible (md): study design (pro = prospec-tive study), number of patients (Patient no.), implants placed per patient (Impl/pat), length of follow-up (in years), assess-ment scale (+/– = polar questions), and within-patient comparison pre- vs. post-implantation.

Study design

Jaw Patient no.

Impl /pat

Follow-up Scale Within patient

Stellingsma et al, 200379 pro md 19 4 1 a 0-10 +/-

yes



Cho and co-workers (2007)82 investigated 10 patients (7 women, 3 men, mean age: 58 years) with edentulous mandibles in a retrospective study with a mean follow-up of 22.8 months (range: 14 to 36 months). Inclusion criteria involved dissatisfaction with conventional prostheses due to lack of stability. A total of 34 one-piece narrow-diameter implants (Atlas; Dentatus, New York, NY, USA) with a diam-eter of 2.4 mm were placed in the interforaminal region. Existing mandibular dentures were relined to establish adequate retention and allow immedi-ate function. Patient satisfaction with complete as well as implant-retained prostheses was assessed 2 months after surgery using the following patient sat-isfaction questionnaire: 1) Does your lower denture stay in place during function?; 2) Are you comfort-able with your lower denture?; 3) How well does your lower denture fit?; 4) Do your upper and lower dentures fit well together?; 5) Are you satisfied with your lower denture?; 6) How well do you speak with your lower denture?; 7) How well do people under-stand you when you speak?; 8) How happy are you with your facial appearance with your dentures in place?; and 9) Do you feel comfortable with your social life with your dentures? (0 = very dissatis-fied to 10 = very satisfied). Patients rated implant-retained dentures better than their previously worn conventional dentures in all categories: 7.8 vs. 3.0 for question 1 (+48%), 8.1 vs. 3.4 for question 2 (+47%), 8.6 vs. 2.2 for question 3 (+54%), 9.0 vs. 4.0 for question 4 (+50%), 8.2 vs. 1.6 for question 5 (+66%), 9.3 vs. 5.4 for question 6 (+39%), 9.4 vs.

7.6 for question 7 (+18%), 8.4 vs. 7.2 for question 8 (+12%), and 8.4 vs. 5.6 for question 9 (+28%), however, no statistical comparison was attempted.

Griffitts and co-workers (2005)83 investigated 24 patients (mean age: 67 years) with edentulous mandibles in a prospective questionnaire study with a mean follow-up of 0.5 years. No further inclusion criteria were stated. In each patient 4 narrow-diam-eter implants 10 to 18 mm in length and 1.8 mm in diameter (Sendax MDI, IMTEC; 3M ESPE, Seefeld, Germany) were placed between the mental for-amina. The complete dentures were retrofitted with the MDI housings and the implants were immedi-ately loaded. Patient satisfaction regarding comfort, retention, chewing ability and speaking ability was assessed on a scale of 1 = poor to 10 = excellent. The patients rated satisfaction before as well as after surgery when receiving the questionnaire 6 months after surgery. Significant improvement was noted in all 4 categories: pre- vs. postoperative scores were 2.2 vs. 9.4 for comfort (+71%), 1.7 vs. 9.6 for reten-tion (+79%), 2.3 vs. 9.3 for chewing ability (+73%) and 5.3 vs. 8.5 for speaking ability (+32%).

Jofre and co-workers (2013)84 investigated 15 patients (10 women, 5 men, mean age: 75 years) with edentulous mandibles in a randomised con-trolled trial with a follow-up of 1 year. Inclusion criteria involved being aged between 45 and 90 years, experience with instability of conventional prostheses and absence of temporomandibular dis-orders. The test group received a total of 30 nar-row-diameter implants, 1.8 x 15 mm (Sendax MDI,

Table 4 Studies on patient satisfaction with narrow-diameter implants in edentulous jaws (mx = maxilla, md = mandible): study design (RCT = randomised controlled trial, pro = prospective study, retro = retrospective study), number of patients (Patient no.), implants placed per patient (Impl/pat), length of follow-up (in years), assessment scale (OHIP = Oral Health Impact Profile, +/– = polar questions), and within-patient comparison pre- vs. post-implantation (*both ratings assessed after implant treatment).

Study design

Jaw Patient no.

Impl /pat

Follow- up

Scale Within patient

Brandt et al, 201281 retro md 24 4 2 a 1–7 yes*

Cho et al, 200782 retro md 10 2–4 0.2 a 0–10 yes*

Griffitts et al, 200583 pro md 24 4 0.5 a 1–10 yes*

Jofre et al, 201384 RCT md 15 2 1 a OHIP yes

Morneburg & Pröschel, 200886 pro md 37 2 6 a 0–10 yes

Šćepanović et al, 201287 pro md 30 4 1 a OHIP 0–10

yes

Veltri et al, 200889 pro mx 12 5-8 1 a +/- no



IMTEC) using surgical guides and immediate load-ing with a pre-fabricated bar attachment, while the control group comprised 15 patients with complete mandibular dentures. Oral health-related quality of life was assessed using a version of the Oral Health Impact Profile (OHIP-EDENT) with 19 items85 prior to intervention as well as 1 year after surgery. While no differences in the baseline OHIP scores could be seen between test (37) and control (37) group, a significant effect of implant treatment could be observed. Treatment with narrow-diameter implants significantly reduced OHIP-scores by 26 points, i.e. 34.2%, to an average score of 11.

Morneburg and Pröschel (2008)86 investigated 37 patients (mean age: 69 years) with edentulous mandibles in a prospective study with a mean fol-low-up of 6 years. Inclusion criteria involved severe ridge resorption (either completely level or only slightly raised). In a two-stage procedure, a total of 74 implants with a diameter of 2.5 mm (MicroPlant, Komet Brasseler Group, Lemgo, Germany) were placed in the mandibular canine/lateral incisor re-gion. All patients received overdentures with either magnetic or O-ring attachments. Patient satisfaction was assessed prior to implant surgery as well as 6 weeks after overdenture connection, ranging from 0 = totally dissatisfied to 10 = excellent with respect to denture retention and chewing ability. Pre- and postoperative ratings were 2.0 vs. 8.4 regarding denture retention (+64%), and 2.1 vs. 9.1 regard-ing chewing ability (+70%), both showing highly significant increase.

Šćepanović and co-workers (2012)87 investi-gated 30 patients (16 women, 14 men, age range: 45 to 63) with edentulous mandibles in a prospective observational study with a follow-up of 1 year after implant placement and immediate loading. Inclusion criteria involved patients edentulous in both jaws, mandibular bone height of at least 15 mm and min-imum residual bone width of 5 mm. In each patient 4 one-piece mini-implants, 1.8 mm in diameter and 13 mm in length (MDI, 3M ESPE) were placed and the O-ball heads were connected to the metal hous-ings in the mandibular overdentures within 24 h after surgery. Patient satisfaction was assessed on a VAS (labelled as ‘completely dissatisfied’ to ‘completely satisfied’) with regards to comfort, stability, speak-ing ability, ability to maintain hygiene, aesthetics and

general chewing ability, as suggested by Awad and Feine88. In addition, subjective chewing efficiency was also assessed on a VAS (labelled ‘impossible to chew’ to ‘not hard to chew at all’) regarding six types of food: carrots; apples; cheese; bread; sau-sages and lettuce. Oral health-related quality of life was assessed using a version of the Oral Health Impact Profile (OHIP-EDENT) with 19 items85 using a six-point Lickert scale (1 = never to 6 = always) 15 weeks after they received conventional prostheses as well as 15 weeks after implant placement (while blinded to their baseline scores). Patient satisfaction increased significantly before vs. after implant treat-ment regarding comfort (5.4 vs. 7.5, +21%), stabil-ity (5.3 vs. 8.3, +30%), speaking ability (7.0 vs. 8.6, +16%), and chewing ability (5.5 vs. 7.6, +21%), while no difference regarding hygiene (7.2 vs. 7.5, +3%) and aesthetics (8.4 vs. 8.7, +3%) could be noted. Subjective ability to chew carrots (5.4 vs. 7.0, +16%), apples (5.9 vs. 8.1, +22%), cheese (7.1 vs. 8.6, +15%), bread (5.9 vs. 8.4, +25%), sausages (5.4 vs. 8.4, +30%), as well as lettuce (6.2 vs. 8.1, +19%) improved significantly. Mean OHIP-scores improved from 74.1 pre- to 50.6 post-implantation (mean paired difference: 23.5).

Veltri and co-workers (2008)89 investigated 12 patients (8 women, 4 men, mean age: 58 years) with edentulous maxillae in a prospective study with a follow-up of 1 year after loading. Inclusion criteria involved knife-edged resorption with maxillary bone width below 4 mm, however, sufficient residual bone height. A total of 73 implants of 3.5 mm diameter (MicroThread, Astra Tech; Dentsply, York, PA, USA) were placed according to a two-stage surgical pro-tocol. Implant lengths between 9 and 17 mm were used. After 6 months of healing, all patients were rehabilitated with fixed metal acrylic prostheses. Patient satisfaction was assessed by occurrence of imperfect pronunciation (polar question). One year after rehabilitation, 10 patients (83%) were satisfied with the phonetic outcome.

n Reduced number of implants

Burns and co-workers (2011)90 investigated 30 patients (11 women, 19 men, mean age: 59 years) with edentulous mandibles in a prospective ran-domised clinical trial. Inclusion criteria involved



adequate bone quantity to minimally accommo-date 4 implants of 3.75 mm diameter and at least 1 year of previous conventional complete denture treatment history. Four implants (Brånemark, Nobel Biocare) were placed in the anterior mandible and subjected to submucosal healing for 4 to 6 months. Following a crossover study design, 3 different over-denture attachment types were delivered to each patient for 1 year, each in randomised treatment sequences: 4-implant bar attachment; 2-implant bar attachment; and 2-implant O-ring attachments (Ball Attachment, Nobel Biocare). Patient satisfac-tion was assessed via a 40-item denture complaint questionnaire (0 = not at all, 1 = a little, 2 = quite a lot, 3 = extremely) that did not demonstrate equiva-lence of treatment modalities. Treatment preference was assessed in the following categories: overall best satisfied (64% vs. 32%); selected treatment (68% vs. 32%); easiest to get used to (56% vs. 20%); best denture retention (52% vs. 32%); best able to chew (56% vs. 24%); best able to speak (40% vs. 20%); greatest movement (64% vs. 8%); and easiest to clean (56% vs. 1%), revealing significantly higher patient acceptance with prostheses supported by 2 vs. 4 implants (Table 5).

De Bruyn and co-workers (2001)91 investigated 20 patients (12 women, 8 men, mean age: 64 years) with edentulous mandibles rehabilitated by fixed

prostheses on 3 implants only in a prospective multi-centre study with a follow-up of 1 year. Inclusion cri-teria involved enough bone volume for the insertion of implants 13 to 15 mm in length and edentulism in the mandible for at least 6 months. The 3 implants (1 in the symphysis area and 2 anterior to the mental foramina) with a regular platform of 3.75 or 4 mm and 13 to 15 mm length (Nobel Biocare) were placed in each patient to support titanium milled frame-works mounted with acrylic teeth after a mean heal-ing period of 1 month (range: 4 to 53 days). Patient satisfaction was assessed on a 6-grade scale rang-ing from ‘negative’ to ‘positive’ or ‘never’ to ‘always’ regarding general satisfaction, phonetic problems and comfort problems related to eating. Satisfaction was 77% in general, 85% with phonetics and 85% with eating (compared to 7%, 10% and 25% prior to sur-gery wearing complete prostheses, respectively). No statistical comparison was attempted.

De Kok and co-workers (2011)92 investigated 20 patients (11 women, 9 men, mean age: 63 years) with edentulous mandibles in a randomised controlled pilot trial with a follow-up of 1 year. Inclusion criteria involved mandibular bone height of at least 10 mm in the parasymphysis area and complete edentulism for at least 3 months. Two-implant-supported over-dentures were compared to three-implant-supported dentures. A total of 50 implants (OsseoSpeed, Astra

Table 5 Studies on patient satisfaction with a reduced number of implants in edentulous jaws (mx = maxilla, md = mandi-ble): study design (RCT = randomised controlled trial, pro = prospective study, co = cross-over design), number of patients (Patient no.), implants placed per patient (Impl/pat), length of follow-up (in years), assessment scale (OHIP = Oral Health Impact Profile, +/– = polar questions), and within-patient comparison pre- vs. post-implantation.

Study design

Jaw Patient no. Impl /pat


Burns et al, 201190 RCT (co)

md 30 2 4

1 a 3–0 +/-

yes

De Bruyn et al, 200191

pro md 20 3 1 a 1–6 yes

De Kok et al, 201192 RCT md 10 10

2 3

1 a OHIP 0–100

yes

Slot et al, 201394 RCT mx 25 25

4 6

1 a 1–10 yes

Visser et al, 200595 = Meijer et al, 200996

RCT md 29 29

2 4

5 a 3–0 yes

Walton et al, 200997 RCT md 38 37

1 2

1 a 0–100 yes

Weinländer et al, 201098

pro md 21 46

2 4

5 a 1–5 no



Tech; Dentsply) were placed. Patient satisfaction was assessed on a visual analogue scale (complete dissat-isfaction to complete satisfaction) regarding general satisfaction, denture satisfaction, ease of cleaning, stability, retention, comfort, ease of chewing, ease of speaking and aesthetics. Oral health-related quality of life was assessed using the full version of the Oral Health Impact Profile (OHIP) with 49 items93. In both groups, all VAS-ratings as well as the OHIP-scores improved significantly compared to baseline. No dif-ference between 3-implant and 2-implant groups were found regarding general satisfaction (95% vs. 94%), denture satisfaction (96% vs. 96%), stability (96% vs. 94%), retention (97% vs. 95%), comfort (98% vs. 95%), ease of chewing (94% vs. 92%), ease of speaking (89% vs. 91%), aesthetics (98% vs. 95%), as well as oral health-related quality of life (18.9 vs. 20.2). However, ease of cleaning was sig-nificantly worse with 3 vs. 2 implants (89% vs. 97%).

Slot and co-workers (2013)94 investigated 50 patients (27 women, 23 men, mean age: 59 years) with edentulous maxillae in a randomised controlled study on bar-retained overdentures, of which 49 completed the 1-year follow-up. Inclusion criteria involved lack of retention and stability of the upper complete denture and sufficient bone volume in the anterior maxilla (at least 12 mm in height and 5 mm in width). Half of the patients received 4 implants (OsseoSpeed, Astra Tech, Dentsply), in the remainder 25 patients 6 implants were placed. After 3 months of submucosal healing both groups received milled bar-retained overdentures without palatal coverage. Patient satisfaction was assessed by a questionnaire consisting of 54 items (each rated between 0 = no complaints and 3 = severe complaints) divided into 6 subscales: 9 items concerning functional problems of the lower denture; 9 items concerning functional problems of the upper denture; 18 items concern-ing functional problems/complaints in general; 3 items concerning facial aesthetics; 3 items concern-ing accidental lip, cheek and tongue biting (neutral space); and 12 items concerning denture aesthetics. In addition, a Chewing Ability Questionnaire rating 9 different kinds of food (0 = good to 2 = bad) was filled out. Patients’ overall denture satisfaction was expressed on a 10-point rating scale (1 = very bad to 10 = excellent). There was significant improvement after vs. before implant placement in all scales, both

in the 4-implant group (8.9 vs. 4.0) and the 6-im-plant group (8.9 vs. 4.1). However, there were no significant differences between the groups.

Visser and co-workers (2005)95 investigated 60 patients (39 women, 21 men, mean age: 55 years) with edentulous mandibles in a randomised con-trolled trial, of which 56 patients completed the 5-year follow-up. Inclusion criteria involved residual bone height of 12 to 18 mm in the anterior mandible and an edentulous period of at least 2 years prior to surgery. Half of the patients received 2 implants (IMZ, Friedrichsfeld, Mannheim, Germany); in the other 30 patients, 4 implants were placed. After 3 months of submucosal healing, bar-retained mandibular over-dentures and new maxillary complete dentures were delivered. Patient satisfaction was assessed by the same 54-item questionnaire used by Slot and co-workers (2013)94. Significant improvement of patient satisfaction after 5 years of loading could be observed only in the first subscale concerning overdenture function: mean pre-treatment scores were 2.2 in both groups and improved to 0.3 in both groups without any differences between the 2-implant vs. the 4-implant group. Meijer and co-workers (2009)96 published 10-year results of the same patient group, again without revealing differences between the groups (score 0.4 vs. 0.5, 3 patients with 4 implants and 7 patients with 6 implants lost to follow-up).

Walton and co-workers (2009)97 investigated 86 patients (43 women, 43 men, mean age: 67 years) with edentulous mandibles in a randomised controlled trial, of which 74 patients completed the 1-year follow-up. Inclusion criteria involved a resid-ual bone height of at least 6 mm in the anterior man-dible and at least 6 month’s experience with con-ventional complete dentures that were aesthetically satisfactory to the patient and technically accept-able in the judgement of the study prosthodontists. Thirty-eight patients were randomised to the single-implant group, while 37 patients received 2 implants (ITI Solid Screw SLA, Straumann, Waldenburg, Swit-zerland) to retain overdenture via ball attachments (ITI spherical stud, Straumann) after a healing period of 6 weeks. Patient satisfaction was assessed by VAS-ratings in 8 denture-related issues, both prior to as well as 1 year after rehabilitation: pain; comfort; appearance; function; stability; speech; hygiene and overall satisfaction. While baseline satisfaction scores



differed between the single-implant (VAS = 29%) and double-implant group (VAS = 51%), however not significantly; no difference in patient satisfac-tion after 1 year of loading could be found (93% vs. 94%). Improvement in overall satisfaction was highly significant in both groups; however, differ-ences between the groups may be related to differ-ences in the baseline values.

Weinländer and co-workers (2010)98 investigated 76 consecutive patients (42 women, 34 men, mean age: 60 years) with edentulous mandibles in a prospec-tive comparative study with a minimum follow-up of 5 years. Inclusion criteria involved atrophic mandibles (Cawood and Howell99-class III to V). Twenty-one patients received 2 interforaminal implants (IMZ, Fri-aloc or Camlog) with an ovoid bar; 22 patients received 4 implants with multiple ovoid bars (implant-retained overdenture); and 24 patients received 4 implants with a milled bar (implant-supported prosthesis). Patient satisfaction was assessed as not satisfactory, adequate, satisfactory, good, or excellent (score ranging from 1 to 5) regarding general satisfaction, chewing ability, denture stability, speech, and aesthetics. Mean ratings did not differ between the groups (5.0 for general satisfaction, 5.0 for chewing ability, 5.0 for denture stability, 4.6 for speech, and 4.5 for aesthetics).

n Tilted implant placement

Agliardi and co-workers (2009)100 investigated 20 consecutive patients (9 women, 11 men, mean age: 57 years) with edentulous maxillae rehabilitated by fixed prostheses on 4 implants in a prospective study with a mean follow up of 27.2 months (range: 18 to 42 months). Inclusion criteria involved sufficient bone for the placement of implants at least 10 mm long and 4 mm in diameter. A total of 120 implants were placed (30 Brånemark MK IV and 90 NobelSpeedy Groovy, Nobel Biocare), the posterior implants were tilted between 30 and 45 degrees. Acrylic resin provi-sional prostheses were delivered within 4 h after sur-gery. Patient satisfaction was rated as excellent, very good, good, sufficient, or poor, regarding aesthetics, phonetics and masticatory function at baseline at 6 months (all patients) and 1 year after surgery (8 patients lost to follow-up). Excellent or very good ratings were given in 85%, 85%, and 83% regard-ing aesthetics, in 80%, 70%, and 92% regarding phonetics, and in 75%, 65%, and 75% regarding mastication, respectively (Table 6).

Antoun and co-workers (2012)101 investigated 44 patients (32 women, 12 men, mean age: 70 years) with 13 edentulous maxillae and 31 edentu-

Table 6 Studies on patient satisfaction with tilted implant placement in edentulous jaws (mx = maxilla, md = mandible): study design (pro = prospective study, retro = retrospective study), number of patients (Patient no.), implants placed per patient (Impl/pat), length of follow-up (in years), assessment scale (+/– = polar questions), and within-patient comparison pre- vs. post-implantation.

Study design


Follow-up Scale Within patient

Agliardi et al, 2009100 pro mx 20 6 1 a 1–5 no

Antoun et al, 2012101 retro 13 mx 31 md

44 4–5 1.5 a 0–10 yes

Babbush, 2012102 retro 167 mx 113 md

250 4 - 1–5 no

Capelli et al, 2007103 pro 41 mx 24 md

65 4–6 2.0 a +/- no

Fortin et al, 2002104 retro mx 45 3–7 5 a +/- no

Maló et al, 2012105 pro 79 mx 133 md

142 4 2.2 a +/- no

Mattsson et al, 1999106 pro mx 15 4–6 3.8 a +/- no

Peñarrocha et al, 2010107 retro mx 12 4 1 a 1–10 no

Rosén & Gynther, 2007108 retro mx 19 4–6 8–12 a +/- no

Testori et al, 2008109 pro mx 28 6 1 a 1–5 no

Weinstein et al, 2012110 pro md 20 4 0.5 a 1–5 no



lous mandibles in a retrospective study with a mean follow-up of 17.6 months (range: 3 to 56 months). Inclusion criteria involved favourable occlusal con-text (restriction to Angle Class I and II). A total of 78 implants (Brånemark TiUnite, Nobel Biocare) were placed in the maxilla (All-on-Six concept) and 124 in the mandible (All-on-Four concept). All patients received screw-retained full-arch acrylic resin provi-sional prostheses within 24 h after surgery. Patient satisfaction was assessed (0 to 10) before interven-tion and at the last follow-up visit. Overall, patients were satisfied or very satisfied with the procedure. Aesthetics, mastication, and comfort increased from 3.6 to 8.5 (+49%), from 3.0 to 8.3 (+53%) and from 2.8 to 8.8 (+60%), respectively. Pain, swell-ing, and haematoma was unpleasant for 20%, 33%, and 53%, respectively. However 98% declared they would recommend this treatment to others.

Babbush (2012)102 investigated 250 patients (143 women, 107 men) with 167 edentulous maxil-lae and 113 edentulous mandibles in a retrospective study. Patients received immediate provisional fixed prostheses on 4 implants (NobelActive, Nobel Bio-care) according to the All-on-Four concept in one or both jaws with the 2 posterior implants tilted distally. After treatment they completed the 20-question Edentulous Patient Impact Questionnaire (EPIQ). Patient satisfaction was 95% (74% extremely satis-fied, 21% satisfied) and 98% would recommend similar treatment to a friend or colleague. Some 75% rated their postsurgical discomfort as being less than expected and 70% reported less swelling than expected. And 60% reported better chewing and 32% better speaking capabilities with the temporary prosthesis then they experienced preoperatively.

Capelli and co-workers (2007)103 investigated 65 consecutive patients (43 women, 22 men, mean age: 59 years) with 41 edentulous maxillae and 24 edentulous mandibles in a prospective multicentre study with a mean follow-up of 24.3 months. Inclu-sion criteria involved severe atrophy of posterior jaw regions that would have necessitated bone augmen-tation surgery. A total of 246 implants were placed in the maxilla (6 per jaw) and 96 implants in the mandible (4 per jaw), while posterior implants were tilted between 25 and 35 degrees (Osseotite NT, Biomet 3i, Palm Beach Gardens, FI, USA). Temporary fixed prostheses were delivered within 48 h. Patient

satisfaction was assessed by polar questions regard-ing aesthetics, phonetics, ease of maintenance and functional efficiency. All patients were totally satis-fied with all aspects of treatment.

Fortin and co-workers (2002)104 investigated 45 consecutive patients (30 women, 15 men, 96% between 31 and 70 years of age) with edentulous maxillae in a retrospective study with a follow-up of 5 years. The inclusion criteria involved sufficient bone for implants with a minimum diameter of 3.75 mm and necessity of lip support or position of the lip when smiling requiring a flange extension to the prosthesis. A total of 245 implants (Bråne-mark system, Nobel Biocare) were placed, of which 90 posteriorly placed implants were tilted to avoid the maxillary sinus. All patients received full-arch, double-structure Marius implant prostheses. Patient satisfaction regarding phonetics, aesthetics and psy-chological and functional aspects was assessed by polar questions. All patients were satisfied with each of the four aspects.

Maló and co-workers (2012)105 investigated 142 patients (86 women, 56 men, mean age: 54 years) with 79 edentulous maxillae and 133 edentulous mandibles in a prospective cohort study with a mean follow-up of 2.2 years. Inclusion criteria involved the possibility of placing implants at least 10 mm length. According to the All-on-Four concept (30 to 45 degrees tilting of the posterior implants) 4 implants per jaw were placed (Brånemark MK III, Brånemark MK IV, or NobelSpeedy, Nobel Biocare). Full-arch acrylic resin prostheses were delivered on the day of surgery. Patient satisfaction was assessed by polar questions regarding aesthetic complaints, phonetic complaints, comfort complaints and hygienic com-plaints. No complications were registered during the study period.

Mattsson and co-workers (1999)106 investi-gated 15 patients (11 women, 4 men, mean age: 59 years) with edentulous maxillae rehabilitated by fixed prostheses on 4 implants in a prospective study with a mean follow-up of 3.8 years. Inclu-sion criteria involved maxillary bone dimension not more than 10 mm in the vertical aspect and more than 4 mm thickness (Cawood and Howell99-class V or VI). A total of 86 implants (Brånemark, Nobel Biocare) were placed, the two posterior of 4 to 6 implants per patient were angulated according to the



anatomy of the anterior-medial wall and floor of the maxillary sinus. After a submerged healing period of at least 6 months fixed superstructures were made of cobalt-chromium (6 patients), silver-palladium (6 patients) or titanium (3 patients). Patient satisfaction was assessed by polar questions regarding aesthetics and phonetics. The aesthetic outcome was consid-ered to be satisfactory for all patients (100%). Pho-netic problems were initially reported by 4 patients (27%), but no longer perceived as socially limiting at the 1-year recall.

Peñarrocha and co-workers (2010)107 investi-gated 12 patients (10 women, 2 men, mean age: 61 years) with edentulous maxillae in a retrospective case series with 1-year follow-up. Inclusion criteria involved severe maxillary resorption (Cawood and Howell99-class V). A total of 48 implants (Impladent or Straumann) were placed in tilted, palatal posi-tions in the anterior maxillary buttress. Overdentures were fabricated 3 to 4 months after implant surgery. Patient satisfaction was assessed on a 10-cm visual VAS using the anchor words 1 = totally dissatisfied to 10 = completely satisfied in the following categories: general satisfaction with the implant-retained pros-thesis; comfort and stability; ability to speak; ability to perform oral hygiene; aesthetics; self-esteem; and function. The mean general level of satisfaction was 8.5, comfort and stability 8.0, ability to speak 9.0, ease of cleaning 8.5, aesthetics 8.5 and function 8.5 after 1 year of loading.

Rosén and Gynther (2007)108 investigated 19 patients (13 women, 6 men, mean age: 60 years) with edentulous maxillae in a retrospective long-term follow-up study (8- to 12-year follow-up). Inclusion criteria involved severe resorption (Cawood and Howell99-class V or VI) and posterior implants tilted in an angle of more than 30 degrees. In total, 103 implants (Brånemark MK II, Nobel Biocare) were placed in the anterior maxilla, 4 to 6 in each patient. Second-stage surgery was performed after 6 months and all patients received metal-acrylic fixed full-arch prostheses. Patient satisfaction was assessed by polar questions regarding pre- or postoperative disorders or problems, including paraesthesia, infection of the maxillary sinus, oral hygiene difficulties, temporo-mandibular joint disorders, problems with biting or chewing, and phonetic or aesthetic problems. One patient had problems with biting (5%), 8 patients

reported speaking differently (42%) and 7 patients reported aesthetic problems (37%).

Testori and co-workers (2008)109 investigated 41 patients (26 women, 15 men, mean age: 59 years) with edentulous maxillae in a prospective multicen-tre study, of which 28 patients (68%) completed the 1-year follow-up. Inclusion criteria involved severely resorbed maxillae with at least 4 mm height and 6 mm width in the first premolar region that would have needed bone augmentation for placing implants in a more posterior location. In each patient 6 implants were placed (Osseotite NT, Biomet 3i), with the 2 posterior implants tilted between 30 and 35 degrees. Provisional screw-retained full-arch prostheses were delivered within 48 h after surgery. Patient satisfaction was assessed by rating aesthet-ics, phonetics, ease of maintenance and functional efficiency as either excellent, very good, good, suffi-cient or poor. Patients were satisfied with aesthetics, phonetics, maintenance, and function (ratings excel-lent or very good) in 75%, 86%, 36%, and 69%, respectively. All patients affirmed that their quality of life had improved after the treatment.

Weinstein and co-workers (2012)110 investigated 20 patients (12 women, 8 men, mean age: 61 years) with edentulous mandibles in a prospective obser-vational study (mean follow-up: 31 months, range: 20 to 48 months) on the effect of fixed prostheses on 4 implants. Inclusion criteria involved residual bone height of at least 10 mm and bone width of at least 4 mm and patients who manifested a clear preference for fixed implant-supported rehabilita-tion, but refused any kind of bone augmentation procedure. Two anterior implants were placed ax-ially and 2 posterior implants were tilted (Brånemark System MK IV or NobelSpeedy Groovy, Nobel Bio-care) with an insertion torque of at least 30 Ncm. All patients received immediately loaded full-arch fixed prostheses. Patient satisfaction was assessed on a 5-point Lickert-type scale (1 = poor to 5 = excel-lent) by means of a questionnaire delivered at the 6-, 12-, and 24-month visit. All patients completed the 6-month follow-up and 18 patients (90%) responded after 1 year. The mean ratings regarding function, aesthetics and phonetics were 3.9, 3.4, and 3.7 after 6 months and 4.0, 3.7, and 3.8 after 1 year, respectively. No significant differences were noted between the 6-months and 1-year evaluation.



n Zygomatic fixtures

Bothur and Garsten (2010)111 investigated 7 patients (5 women, 2 men, mean age: 64 years) with eden-tulous maxillae in a retrospective case series with a follow-up of 4 months. Inclusion criteria involved severe atrophy of the maxilla (Cawood and How-ell99-class VI) with extensive resorption into the basal bone. The patients received a total of 28 zygomatic fixtures and 5 conventional implants (Brånemark System, Nobel Biocare) to support fixed prostheses after a mean healing period of 6.5 months. Patients judged their speaking ability prior to implant treat-ment as well as 4 months after surgery on a scale of 0 to 10. Mean subjective ratings were 6.9 before surgery, 5.9 after one week and 7.1 after 4 months of loading (Table 7).

Davó and Pons (2013)112 investigated 17 con-secutive patients (10 women, 7 mean, mean age: 58 years) with edentulous maxillae in a prospective study with a follow-up of 3 years. Inclusion criteria involved severe maxillary atrophy (Cawood and Howell99-class IV or V). In each patient 4 zygomatic fixtures (Brånemark System, Nobel Biocare) of 30 to 52.5 mm length were placed and subjected to immediate loading (15 fixed screw-retained pros-theses and 2 overdentures). Oral health-related quality of life was assessed using a short version of the Oral Health Impact Profile (OHIP) with 14 items113. The average OHIP-score was 2.7 after 3 years of loading (no baseline value was available for comparison).

Farzad and co-workers (2006)114 investigated 11 patients (10 women, 1 man, mean age: 58 years) with edentulous maxillae in a retrospective study with a follow up of 18 to 46 months. Inclusion cri-teria involved insufficient bone volume for routine implant placement in the posterior maxilla. A total of 22 zygomatic fixtures and 42 conventional implants (Nobel Biocare) were placed. After a healing period of 6 to 11 months all patients were provided with fixed prostheses (Procera Implant Bridge titanium framework, Nobel Biocare). Patient satisfaction was assessed on a 10-cm VAS regarding the following questions: 1) How is your chewing ability today?; 2) How was your chewing ability before treatment?; 3) How do you experience the aesthetic results of the treatment?; 4) How did you feel about the overall appearance of your teeth before treatment?; 5) How is your speech today?; 6) How was your speech before treatment? (endpoints of the scale were defined as ‘best possible’ and ‘worst possible’). Significant improvement was seen with regards to chewing and aesthetics, however not for speech with mean differences before vs. after treatment of 4.3, 4.0 and 1.0, respectively.

Peñarrocha and co-workers (2007)115 inves-tigated 23 patients (12 women, 11 men, mean age: 53 years) with edentulous maxillae in a retro-spective clinical study with a follow-up of 1 year. No further inclusion criteria were stated. Patients received 1 to 2 zygomatic fixtures (Nobel Biocare) and 3 to 6 additional implants (Defcon; Impla dent, Barcelona, Spain) in the anterior maxilla – in total

Table 7 Studies on patient satisfaction with zygomatic fixtures (zyg) in combination with regular implants (reg) in edentulous maxillae (mx): study design (pro = prospective study, retro = retrospective study), number of patients (Patient no.), implants placed per patient (Impl/pat), length of follow-up (in years), assessment scale (OHIP = Oral Health Impact Profile, +/– = polar questions), and within-patient comparison pre- vs. post-implantation (*both ratings assessed after implant treatment).

Study design



Bothur & Garsten, 2010111 retro mx 7 2–5 zyg 0–3 reg

0.3 a 0–10 yes

Davó & Pons, 2013,112 pro mx 17 4 zyg 3 a OHIP no

Farzad et al, 2006114 retro mx 11 2 zyg 2–4 reg

1.5-3.8 a 0–10 yes*

Peñarrocha et al, 2007115 retro mx 23 1–2 zyg 3–6 reg

1 a 0–10 no

Peñarrocha et al, 2009116 = 2013117

retro mx 13 0–2 zyg 2–7 reg

5.8 a 0–10 no

Sartori et al, 2012118 pro mx 16 5.9 1 a +/- no



144 implants. All patients received fixed prostheses. Patient satisfaction was assessed on a 10-cm visual analogue scale ranging from 0 = totally dissatisfied to 10 = completely satisfied with regards to gen-eral satisfaction with the implant-retained prosthe-sis, comfort and stability, ability to speak, ease of cleaning, aesthetics, self-esteem and functionality. Mean patients’ ratings were 9.7 for general satis-faction, 9.8 for comfort and stability, 9.8 for aes-thetics, 9.8 for ease of cleaning, 9.8 for ability to speak, 9.8 for self-esteem and 9.7 for functionality. Ratings regarding aesthetics were significantly bet-ter than in the control group without zygomatic implants (8.9).

Peñarrocha and co-workers (2009)116 investi-gated 13 patients (8 women, 5 men, mean age: 55 years) with edentulous maxillae in a retrospective study and reported the results after a mean follow-up of 70 months (range: 24 to 132 months) in a sub-sequent article in 2013117. Inclusion criteria involved severe maxillary atrophy (Cawood and Howell99-class IV or V) and implants placed in the nasopala-tine canal. A total of 6 zygomatic fixtures and 72 conventional implants (Impladent or Straumann). All patients received fixed screw-retained full-arch prostheses after 12 weeks of submerged healing. Patient satisfaction was assessed on a 10-cm visual analogue scale regarding general satisfaction with the implant-retained prosthesis, comfort and sta-bility, ability to speak, ease of cleaning, aesthetics, self-esteem, and function (anchor words: ‘totally dissatisfied’ and ‘completely satisfied’). Average patient ratings were 9.0 for general satisfaction, 9.7 for comfort and stability, 9.5 for ability to speak, 8.5 for function, aesthetics and self-esteem, and 9.0 for ease of cleaning.

Sartori and co-workers (2012)118 investigated 16 patients (10 women, 6 men, age range: 38 to 77 years) with edentulous maxillae in a prospective clinical study with a follow-up of 1 year. No fur-ther inclusion criteria were stated. Patients received either zygomatic fixtures alone or combined with conventional implants. In total 37 zygomatic fixtures and 58 conventional implants (Alvim Cone Morse, Neodent) were placed. All patients were rehabili-tated with fixed prostheses on titanium cylinders and acrylic teeth within 48 h after surgery. Patient satisfaction was assessed by a self-designed ques-

tionnaire: 1) Satisfaction with treatment (a = com-pletely satisfied, b = satisfied but with some com-plaints, c = had different expectation of treatment, d = unsatisfied); 2) If unsatisfied, the reason is as follows (a = aesthetics, b = discomfort when chew-ing, c = pain, d = phonetics, e = hygiene); 3) Num-ber of clinical sessions required to solve problems after insertion of prosthesis in addition to sched-uled follow-up visits (a = 0 sessions, b = 3 sessions); 4) The complication was related to the following (a = prosthesis, b = implants). Half of the patients were completely satisfied, the other half were satisfied but with some complaints. Dissatisfac-tion was related to aesthetics, chewing, phonetics and hygiene in 4 (25%), 1 (6%), 4 (25%) and 4 cases (25%), respectively. Eight patients required no sessions to solve problems (50%), 6 patients fewer than 3 sessions (38%) and 2 patients more than 3 sessions (13%). Complications were related to the prosthesis in 5 patients (31%) and to the implants in 3 patients (19%).

n Discussion

The present systematic review summarises cur-rent evidence in the literature regarding minimally invasive treatment options for edentulism from the patient’s perspective. Patient satisfaction averaged 91% with flapless implant placement (range: 77 to 100%), 89% with short implants, 87% with narrow-diameter implants (range: 80 to 93%), 90% with a reduced number of implants (range: 77 to 100%), 94% with tilted implant placement (range: 58 to 100%), and 83% with zygomatic fixtures (range: 50 to 97%). Indirect comparison yielded patient prefer-ence towards tilted implant placement compared to a reduced number of implants (P = 0.036) as well as to zygomatic implants (P = 0.001) while no dif-ferences could be seen between other treatment options. It may be concluded that patient satisfac-tion with graftless solutions for implant rehabilitation of completely edentulous jaws is generally high and compares well with implant survival of 97 to 99% reported in reviews of literature (Table 8).

However, no studies comparing patient satisfac-tion with minimally invasive treatment alternatives vs. bone augmentation surgery could be identified in



the current literature. It thus remains unexplored to what extent graftless therapeutic options are actually preferred by patients or whether they offer significant advantages from the patients’ point of view at all. The inherent difficulty of this comparison is certainly due to the fact that it is not possible to perform two – or even more – alternative implant procedures in the same patient (with the possible exception of split-mouth trials that are not easy to conduct as the left and right patient side rarely present with truly com-parable baseline situations with regards to residual al-veolar bone volume and anatomy), particularly when investigating rehabilitation of complete edentulism. Comparative effectiveness research, i.e. within-study comparison in randomised controlled clinical trials, is needed to substantiate the positive appeal of graftless options to potential implant patients and their possi-ble reduction of the indication span for invasive bone augmentation surgery.

Clinical heterogeneity within the studies included in the present literature review arises from a variety of sources involving patient demographics, diverging inclusion criteria (Cawood and Howell99 – classes of atrophy, residual bone volume, period of edentulism, satisfaction with as well as stability of previous remov-able prostheses), use of virtual treatment planning software and surgical templates, implant treatment protocols as well as timing of surgical and prostho-dontic interventions. Multiple confounding factors (such as the type of implant superstructure) may carry the potential to significantly influence patient opinion while not being directly related to the ques-tion under focus, that is amount of surgical invasion. Due to the lack of consensus guidelines regarding the absolute necessity of bone augmentation in defined clinical situations, it remains hard to judge whether

minimally invasive procedures actually represent an alternative to bone graft surgery or merely options associated with reduced patient morbidity.

The major challenge in trying to compare lit-erature results on patient-related outcomes in the present review was the diversity of outcome assess-ment throughout the included studies. While the majority of investigations evaluated subjective treatment satisfaction (92%), only a few examined oral health-related quality of life (11%) or actual patient preferences towards therapeutic options (5%). Methodology and outcome definitions varied extensively with regards to questions asked, scale items and endpoint definitions, anchor words of visual analogue scales, and performance of within-patient comparison. In fact, only a single study87 utilised a validated instrument88 for assessment of patient-centred treatment satisfaction. Conversion of outcome formats to a uniform per cent scale was thus necessary to facilitate outcome comparison, however, must be suspected to have introduced bias to some extent. Future research may pay special attention to uniform and standardised use of vali-dated instruments (such as the Oral Health Impact Profile73) for the assessment of patient opinion as a variable of treatment preference.

n Acknowledgements

The authors would like to express special thanks to Mario Veltri (Siena, Italy) and Swati Ahuja (Mem-phis, TE, US) who kindly provided additional data from their investigations.

Table 8 Patient satisfaction (results from the present review) and implant survival rates (results from literature reviews) with minimally invasive treatment alternatives for graftless rehabilitation of edentulous jaws (n.d. = no data).’

Minimally invasive treatment option Mean patient satisfaction rate (range)

Mean implant survival rate (range)119-121

flapless implant placement 91% (77–100) 97% (92–100)

short implants 89% 97% (74–100)

narrow-diameter implants 87% (80–93) 99% (89–100)

reduced number of implants 90% (77–100) n.d.

tilted implant placement 94% (58–100) 98% (89–100)

zygomatic implants 83% (50–97) 98% (82–100)



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